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Craftsman 24” 291cc LCT engine jammed

6K views 32 replies 15 participants last post by  Sloggernobber 
#1 ·
Hi guys, I was using my 8 year old Craftsman 24” with 291cc LCT engine snowblower and put it away as I normally do. When I came to use it again the electric start won’t turn the engine and neither will the pull start. I took off the covers and exposed the flywheel. I can turn the flywheel about 15 degrees forward and backwards. When I turn it clockwise it hits a hard stop but then turn it counterclockwise and it turns 15 degrees but sounds ‘crunchy’ and then jams too. I have taken the spark plug out and it moves as I turn the flywheel. I can also see the output shaft rotating when I turn the flywheel. I recently did an oil change and used the correct specification oil. I haven’t emptied the oil yet to see if there are any metal pieces.
Do you have any ideas as to what is jamming the flywheel/engine from rotating?
 
#3 ·
Agreed, if you can pull the flywheel you will most likely find the problem.
 
#4 ·
personally i would start by pulling the spark plug and try running some heat into the cylinder. it doesn't happen too often but you do see water working its way into the engine occasionally. don't use the electric start till you know the engine is freed up. best to use the pull start till it is moving.
 
#6 ·
Loosen the nut on the flywheel. They take a pry bar and put some tension on the flywheel from the back side. and take a hammer (Plastic one if you have one) and hit the nut. Don't go crazy, and damage the threads of the nut or crankshaft. It will pop off.
 
#9 · (Edited)
Careful prying as behind the flywheel is of course aluminum and will crack easily. First I've used a wooden board putting it on the back side and banging the board with a hammer. I've also have made a wide wooden wedge from a 2x6 or 2x4 using my table saw. Then I've made an adapter using my puller to go behind it but first used the puller hooks before the adapter. I've worked on aluminium to steel cranks and steel flywheels to steel cranks. When it's off, put Never-Seize or synthetic grease on the crank and threads.
 
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#10 ·
When it's off, put Never-Seize or synthetic grease on the crank and threads.

I use grease on anything that moves and may have to be removed or replaced in the future. I am under the assumption that a flywheel is held tight to the crank shaft by the taper and friction between the two. The key is just to hold it aligned for spark at the correct time. The heavy rotating mass of the flywheel doesn't need any help (grease) to shear the key.
Just my opinion, I've been wrong many times.
 
#11 ·
Not sure where the pry thing comes in with the flywheel. You want to loosen the nut and wack the crank stub with a hammer. Trick is to not damage the threads. A big punch can often help in this regard.

I'm also not sure why a guy would grease it? The taper is there to hold the flywheel securely. They release just fine when assembled dry as they should be.
 
#13 ·
Not sure where the pry thing comes in with the flywheel.

Using a pry bar lifts the flywheel and crank a few thousandths from the engine block and allows the crank to sink down that amount and "usually" free the flywheel.
 
#15 · (Edited)
I'm also not sure why a guy would grease it? The taper is there to hold the flywheel securely. They release just fine when assembled dry as they should be.
Its called corrosion. A form of welding.

And no they do not. Anti size is your friend.

You still get the tension and interference fit, it just comes off the way it does when nice and shiny.

Factory does not care about after service and that is what the dealers have puller for.

Worst was a pump shaft and that was in glycol. It took me 3 days off and on heating and bearing to get the impeller off. Only way I could tell I was winning as a tiny noise and I was getting like 1/128 per cycle movement.

Danged right it want back on with Anti size and it came off find the next time the seal went.
 
#19 ·
Danged right it want back on with Anti size and it came off find the next time the seal went.

I agree, anything that moves and has a "possibility" of needing removal should get grease. I would guess a majority of people here have not and never will need to remove a FLYWHEEL. Why increase the chance of the flywheel slipping by adding a lubricant and shearing a key. Members here that do repairs frequently have a puller or hammer and pry bar. Again, just my opinion.
 
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#17 ·
So, spark plug is out, piston moves and there’s no ice.
I eventually managed to get the flywheel off (struggling as I had knee replacement last month) but you lads were spot on, there is one of the three magnets broken in half and pieces loose inside the flywheel. Good call boys!
Now to find out if the flywheel is still available as I believe that LCT don’t make this engine anymore.
 
#18 · (Edited)
#20 ·
Thanks for the link. So the model of the snowblower is 944.520621 and I saw an exploded view online and one says flywheel assembly SK2911701 ‘electric’ and the other SK2911700 ‘manual’.
Dumb question but as my snowblower is electric and manual pull start, if I bought the ‘electric’ flywheel assembly, that would also work for the manual pull start too?
 
#25 ·
Ok boys, I need your help again. My new flywheel assembly has finally arrived. The original broke as the charging coils inside the magnet area hit one of the steel plates on the magnets and destroyed it. I see on the faces of the other plates mounted on the magnets that they are also scratched from the coils.
How close do the charging coils have to be in relation to the face of the magnets?
Is there a way of setting the coils as it’s really awkward once you go to mount the flywheel assembly?
Also, when retightening the flywheel nut, is there a torque setting for that nut?
Cheers, Nigel
 
#30 ·
The only (Tecumseh) charging coils I've worked with just mounted using round holes (rather than slots), as I recall. I think I just bolted it in-place and continued assembling. For charging purposes, rather than ignition, I'm going to speculate that the gap is less-critical. Especially if they're on the inside, so you can't see then after installing the flywheel.

I'm a big fan of anti-seize, on bolts. But everything I've read has said to not lubricate at least the taper on the crankshaft & flywheel. Even anti-seize on the threads may not be ideal, since the flywheel torque is likely spec'd for clean, dry threads. If you lubricate the threads, the same torque will put more tension on the threads, and therefore also on the flywheel's taper. Over-torquing the flywheel nut can crack the flywheel, as the crankshaft's taper gets pulled into it.

I don't have any LCT engines, but I'd expect there should definitely be a torque spec for the flywheel nut. Too-loose, and the flywheel can spin on the shaft, and shear the flywheel key. Too-tight, and you can damage the flywheel. If you don't have a torque wrench, you may be able to borrow one from an auto parts store.

Some Googling found this for an LCT service manual, it lists a column for 291cc engine torques, including the flywheel nut. Note that they're in N-m, not ft-lbs:
https://www.manualslib.com/manual/1340753/Lct-208cc.html?page=13
 
#33 ·
So I finally got the snowblower working! RedOctobyr, you were correct about the coils, they were self-centred by the two fastening bolts. I showed the damaged flywheel to the distributor and they said that it wasn’t the charge coils that hit the magnets, it was the steel plate that was bonded to the face of one of the magnets that let go and destroyed the magnet - I attached a picture showing the damage.
I set the ignition coil at 0.4mm gap as per the manual. Once reassembled the engine fired up first go with the pull cord.
Anyway I just wanted to say a big thanks to you guys for helping me out. This forum is really helpful with your input.
Cheers, Nigel
 

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